Hollow cathode PVD of nitride and oxide films at low substrate temperatures

Highly oriented crystalline films of aluminum nitride and titanium dioxide were grown from Al or Ti hollow cathode in the nitrogen and oxygen gas mixtures with argon. Films were grown on unheated substrates fixed at a holder with temperature sensor. Both cylindrical and linear hollow cathodes were powered by a radio frequency (r.f.) 13.56 MHz generator and arranged with the gas flow through the cathode. The properties of films deposited on glass and silicon samples at different hollow cathode regimes were tested by X-ray diffraction. The film surface topographies were studied by AFM. Highly oriented crystalline AlN films were deposited at substrate temperatures below 50°C. The best AlN films were deposited in a pure nitrogen plasma. Variations in the deposition parameters at constant r.f. power can be used for modifications of AlN microstructure. Highly textured TiO2 films can be deposited both as anatase or rutile structure, which can be controlled by small changes of the oxygen content in argon. Films can be deposited on selected areas or inside holes by small cylindrical hollow cathodes. However, the deposition process can be scaled up to large substrates by magnetized M-M (Magnets-in-Motion) linear hollow cathodes.